There are many types of marine sensors available for commercial and pleasure craft today. Some of them include instruments for measuring water depth, boat speed, water temperature, as well as, locating fish. Certain depth measuring devices employ an ultrasonic transducer that emits an acoustic beam downwardly from the boat. When the beam strikes something, such as the bottom, the beam reflects an echo back to the transducer. This is converted into electrical energy, amplified and displayed as information on a screen. The information can be displayed on a paper graph, flashing device, or video display.
For the most part, speed, depth, and temperature measuring instruments were three separate devices that required drilling three holes in the hull. Today, these measuring sensors have been combined into a single instrument which provides information with respect to all three parameters of speed, temperature, and depth. However, these single instruments do not allow the sensors to be readily removable from within the hull. In particular, the depth sensor cannot be removed while the vessel is afloat because the size of the transducer element is greater than the opening in the hull.
Despite the above efforts, and that of other workers in the art, a need exists for a through-hull device with that allows the sensing components to be removable from within the hull while the vessel is afloat.